Inelastic proton excitation of high-lying giant resonances

Abstract

Inelastic scattering of 800 MeV protons has been studied for targets of $^{208}\mathrm{Pb}$, $^{144}\mathrm{Sm}$, and $^{116}\mathrm{Sn}$. At excitation energies above particle emission threshold a spectrum of giant resonances is clearly in evidence. Angular distributions were extracted for the high-lying peaks (\ensuremath{\sim}20 MeV excitation energy) in $^{208}\mathrm{Pb}$ and $^{144}\mathrm{Sm}$. Collective model distorted-wave Born approximation analyses of these data show that isoscalar octupole and dipole states dominate the spectra.